Supervisory control system



Dec; 24, 1929. u, WHITE 1,740,556

SUPERVI SORY CONTROL SYSTEM Filed June 1924 8 Sheets-Sheet l WITNESSES:INVENTOR E #gm Thomas M W/r/fe. fiw/ ATTORNEY T. U. WHITE SUPERVISORYCONTROL SYSTEM Dec. 24, 1929.

Filed June 1924 8 Sheets-Sheet INVENTOR Thomas M, W/fl/e.

WITNESSES: fi QM ATTORN EY ea; 24, 1929. T. UVWHITE SUPERVI SORY CONTROLSYSTEM 8 Sheets-Sheet 5 Filed June 6, 1924 wifc/vmg Re/Qgs INVENTORThomas M 1407176 WITNESSES:

Fig.3

/ ATTORNEY Dec. 24, 1929.; WHITE 1,740,556

SUPERVISORY CONTROL SYSTEM Filed June 6, 1924 8 Sheets-Sheet 4 Thomas4/. W/z/fe.

t WITNESSES:

#WM 3 i BY f AT TORNEY T. U. WHITE Dec. 24, 1929.

SUPERVISORY CONTROL SYSTEM 8 Sheets-Sheet Filed June 6, 1924 Omm mm1929- T. u. WHITE SUPERVISORY CONTROL SYSTEM 8 Sheets-Sheet Filed June1924 mNn WNW Em Gum NVENTOR Thomas U. M2176.

WITNESSES:

ATTORN EY Dec. 24, 1929. T. u. WHITE SUPERVISORY CONTROL SYSTEM FiledJune 1924 8 Sheets-Sheet mvb Thomas M. W/r/fe.

TTorNEY Patented Bee. 24, i929 rmsst NT QFFlCE THOMAS u. warns. onrlrrsnunen, rnnnsvtvanra, assrenon. ro wnsmenousn Y nrnc'rnrc &aranurncrunrne ooircranv, a conronarron or :ennnsvrvama surruwrsonrcontract. s'rs'rnm Application filed June My invention relates tosupervisory control systems and particularly'to systems for supervisingand controlling remotely-disposed electrical equipment from a centralpoint or g dispatchers ofice.

Une object of my invention is to provide a supervisory control systemthat may be operated by means of alternating current.

Another object or my invention is to prom vide relay chains at thecentral and distant A still further object; of my invention is toprovide means whereby the number of apparatus units at thedistantstation accessible to the selective apparatus may be increased at verylittle additional cost.

There are other objects of the invention which, together with theforegoing, will be described in the detailed specification which is tofollow. p

Referring now to the drawings, comprising Figures 1 to 8, inclusive, lhave shown, by means of conventional diagrams, the apparatus andcircuits for carrying out my inveution.

The apparatus shown in Figs. 1 to 4, inclusive, is that located at thecentral station or dispatchers ofiice, while the apparatus shown inFigs. 5 to 8, inclusive, is that located at the distant station orsubstation.

ln practicing my invention, 1 provide a 45 chain of counting relays atthe dispatchers office and a chain oi counting relays, corresponding innumber, at the substation in which are located the apparatus units thatit is desired to control and supervise. There are three groups ofselecting relays associated rear. Serial no. 318,359.

with each group of counting relays. In addition, three switching relaysare provided for each group of counting relays. A control circuit islocated at both the dispatchers ofice and station for controlling theoperation of the counting relays. Thecounting relay chains and controlcircuits are connected together by means of a single conductor trunkline using a ground return.

, At the dispatchers oflice, a group of keys are provided, thesecorresponding in number to the number of apparatus unitsthat it isdesired ,to operate. A release key and a control key are located'at tlieoifice.

In order that the dispatcher may be ap prised of the condition of theunits in the substation, two signalling lamps are provided for eachapparatus unit under supervision. Sources of'alternating current of fourdifierent frequencies are provided at the dispatchers ofiice and threesources of alternating current at the substation for controlling theoperation of the apparatus units, the supervisory signalling devices andthe control circuit, as'will appear. Wave filters are also provided atthe substation and dispatchers oflice for determining the operation ofthe apparatus in accordance with the frequency in the control andsignalling circuits.

When the dispatcher desires to control an apparatus unit at the stationor substation, he will operate the key associated with that particularunit in the proper direction, and also the control key. As a result ofthis operation, the control circuits function to operate the relays inthe counting chains in a predetermined sequence. The control circuit isoperated. by the alternate application of two frequencies of alternatingcurrent. Checking means are provided so that, unless the two frequenciesof alternating current are applied alternately, the apparatus does notfunction.

Simultaneously with the first cycle of the counting chains, a switchingrelay is operated at both the dispatchers Office and substation toconnect the relays of one of the auxiliary selecting relay groups andthese relays are operated under the control of the counting relays. Itthe apparatus unit that it is desired to operate is not in thisparticular group, the

counting relay chains will again be operated,

- the previously mentioned switching relay released and anotherswitching relay at the dis patchers office and substation will beoperated to connect the relays of the second auxiliary selecting groups.

In a like manner, if the apparatus unit desired is not accessible tothis group, the

third switching relay-will be operated and the relays of the thirdauxiliary selecting group will be connected.

When the proper apparatus unit is selected, alternating current of apredetermined frequency is sent over the conductor connecting the ofliceand substation to operate a relay at the latter point that is includedin cir- I cuit with the wave filter and that is resonant to thatparticular frequency. The operation of this relay causes the operationof the selected apparatus unit. In the meantime, the control circuit isprevented from operating and the relay selecting apparatus maintainsconnection with the desired apparatus unit. When the apparatus unitoperates, alternating current of a predetermined frequency is appliedtothe trunk conductor and,

a relay, included in circuit with the wave filter, that is resonant tothe particular fre-' condition of the apparatus unit at the station.

The control circuit again begins to function. After all the relays ofthe auxiliary selecting relay groups have 'been operated, the chainrestores to normal.

In the event that an apparatusunit at the substation operates under thecontrol of automatic devices responsive to circuit conditions, theoperation of the supervisory signals takes place insubstantially thesame manner as has been described'under the control of the supervisoryselecting apparatus.

Referring now more particularly to Fig. 1, relays 101 to 124, inclusive,comprise the group of counting relays at the dispatchers oflice. Relays125 and 126 control certain re-' leasing operations.

In Fig. 2, a key K is of ordinary doublethrow type that locks in itsoperated position. There is one such key for each apparatus unit that itis desired to control. key K1 is of the ordinary single-throw nonlockingtype. Relays 200 and 201 are provided for controlling supervisorysignalling devices 231 and 232.

Generators G1 to G4, inclusive, may be of any ordinary type and supplyalternating currents of four different frequencies, namely, 900, 700,300, 1500 cycles, respectively.

Relays 202 to 222, inclusive, Fig. 2, and

relays 100 to 418, inclusive,-Fig. 4 comprise the control circuit forcontrolling the operation of the counting relays-and the operation ofthe switching relays 310 to 312, inclusive,

Fig. 3. Relays 313 and 314-.aie control relays.

Relays 315 to 318, inclusive, are associated with the trunk conductor490 and control the functioning of the apparatus. Relays 300 to 309,inclusive, constitute an auxiliary selecting group of relays. Theserelays have been shown as multi-contact relays of a particular type. Itwill be seen that any type of multicontact relays may be used.

In Fig. 5, relays 500 to 509, inclusive, are the selecting relays of onegroup. Relays 516 to 518, inclusive, are switching relays forcontrolling the connection of the selecting relays to the relays of thecounting chains. The relays 514 and 515 are control relays. Relays 510to 513, inclusive, are relays associated with the signalling circuit andcontrol the functioning of the apparatus in a manner to be described. I

Relays 600 to 618, inclusive, of Fig. 6, and relays 800 to 808,inclusive, Fig. 8, and relays 814 to 82-6., inclusive, constitute thecontrol circuit at the substation. Relays 809 to 811, inclusive andrelay 895 are provided for controllin'g the operation of each circuitbreaker, such as C. The circuit breaker C may be of any ordinary typeand may function in any desired manner. Generators G5, G-6 and G'7 areof the ordinary type and are provided for the purpose of supplyingalternating current of predetermined frequencies, namely, 500, 1300 and1100 cycles, respectively. At 861-, 836 and 838 are represented wa'vefilters, the function of which is to'exclude all frequencies ofalternating current except the predetermined one.

In Fig. 7 relays 700 to 723, inclusive, comprise the relays of thecounting chain at the substation. Relays 7 24 and 725 are controllingrelays. The dispatchers oflice is connected to the substation by meansof a trunk line comprising conductor 490.

The apparatus shown in the drawings having been described in general,its detailed c1rcuit operation will now be explained. For this purpose,it will be assumed that the dispatcher desires to close the circuitbreaker C at the station. To accomplish this result, the

dispatcher will operate the key K in the proper direction, it beingassumed that this operation causes the spring 227 to be operated out ofengagement with its r-estmg con.

tact and the spring 226 to be forced into en'- gagement with its workingcontact. The 'dlS- patcher will then operate the key K1 twice.

Normally, the alternating-current relays 222 and 815 are energized overa circuit which extends from the ungrounded brush of the 150.0 cyclegenerator G-4, back contact and armature 270. alternating-current relay222, wave filter 288, conductor 476, back contact and armature 444, backcontact and armamenses ture 445, trunk conductoril90, armature 659 anditsback contact, armature 661 and its back contact, conductor 683, Wavefilter 861, alternating-current relay 815, and armature 880' and itsback contact to ground.

' The alternating-current relay 222 operates its armatures 289 and290.As shown on the 7 drawing, the armature 290 of the alternat-Zing-current relay-222 forces the armature 287 of the relay 221' intoengagement with its Workingcontact. By this operation, a

circuit is completed extending from ground by Way of armature 289 andits front contact, armature 287 and its. front contact and relay 221 tobattery. The relay 221 is operated to open the original energizingcircuit-10f the relay 216 at armature 285; to complete a circuit for therelay 212 at the front contact of this armature, and to prepare acircuit for the relay 220at armature 286. The relay 212, upon beingenergized, operates its armature 265 to open the locking circuit of therelay 211 which is deenergized. The relay211 retracts its armature 263to prepare a point in the circuit of the relay 214 and retracts itsarmature 264: to complete a circuit extending from ground by Way of saidarmature and its back contact, armature 286 and its front contact andrelay 220 to battery. The relay 220 is operated to prepare a circuit forthe relay 213.

At the substation, the. alternating-current relay 815 is operated tocause its armature 880 to force the armature 86 i ofthe relay 811 intoengagement With'its Working contact. As a result of this operation, acircuit is completed extending from ground by Way of armature 865 andits front contact, armature 864k and its front contact and relay 811 tobattery.

The relay 814: is operated to prepare a circuit for the relay 816 atarmature 863, to

open the original energizing circuit of the relay 820 at armature 862and to complete a circuit for the relay 821 at the front contact of thisarmature. The relay 826 is deenergized by relay 8% to prepare a point inthe circuit of the relay 822 .atarmature 888 and to complete a circuit,at armature 889, extending from ground by Way of back contact and saidarmature, armature 863 and its front contact and relay 816; to battery.The relay 816 is operated to prepare a circuit for the relay 823.Theabove relays are ing circuit is completed for relay 221 overarmature287. This locking circuit holds the .members up thereafter in spite ofthe tendency, to vibrate.

When'the key K1 is operated by the dis patcher, as before described, acircuit is completed extending. from ground by' way of spring 230 andits working contact, armature 269 and its back contact and relay 213 tobattery. The relay 213 is operated to complete a circuit for the relay215 at armature 267, to prepare a point in the circuit of'the relay 219at armature 268 and to complete a circuit 7 extending from ground by wayof back contact and armature 263, armature 266 and its' front contactand relays 214: and 213 to battery. The relay 21 1 is not energized overthis circuit so long as the original energizing circuit of the relay 213is maintained closed.

relay 214 and this'relay is energized. Upon operating, the relay 214opens another point in the original energizing circuit of the relay 213at armature 269 and at armature 270 opens one point in-the circuit ofthe alternating-current relays 222 and 815. The relay 222 is immediatelydeenergized to permit the relay 221 to retract its armatures. Upon beingdeenergized, the relay 221 opens the circuit of the relay 220 atarmature 286, at the baclr'contact of this armature completes a circuitfor the relay 4:10, opens the circuit of the relay 212 at armature. 285and at the back Contact ofthis armature completes a circuit for therelay 216. The'relay 216 immediately operates to establish a lookingcircuit for itself at armature 27 1, tovopen one point in the circuitof'the' relay 219 at armature 27 5, and to complete a circuit extendingfrom ground by Way of front contact and armaturei276, conductor 478,back con-' tact and armature 429, armature 4&2 and its back contact,conductor 488 and switching relay 310 to battery; Therelay 410 operatesto complete one point in the control circuit. The relay 310 operates toconnect the selecting relays 300 to 309, inclusive, so that they may becontrolled by the counting relays 101 to 124, inclusive. I I

The relay 815 at the substation, upon being deenergized, opens the"circuit of the relay 814, thereby permitting this relay to retract itsarmatures. Upon being deenergized, the

relay 814 at armature 863 opens the circuit of the'relay 816, completesa circuit for the relay 618 at the back contactof this armature, opensthe circuit of the relay 821 at armature 862 and at the back contact ofthis armature completes a circuit for the relay 826.

The relay 8l6 is deenergized to open one 'point in the circuit of therelay 823. at

armature 866 and to open one point in the circuit of the relay 817 atarmature 867. The

relay 618, upon being energized, opens another point in the circuit ofthe-relay 815 at armature 661, and at the frontcontact of this armatureprepares one point in the control circuit. The relay 824, upon beingdeenergized, prepares one point in the locking circuit of the relay 826at armature 885. .The relay 820, upon operating, establishes a lookingcircuit for itself over a path extending from ground by way; of backcontact and" relay 518 to battery.. The switching relay 518 is energizedover the above circuit and operates to connect the selecting relays 500to 509, inclusive, of the first group under the control of the countingrelays 700 ,to 723, in-

elusive.

The controlcircuit is now completed over a path Which-extends from theungrounded brush of the alternating-current generator G3 that creates analternating current of 300 cycles, back contact and armature 244,alternating-current relay 205, wave filter 250, back contact andarmature 251; conductor 474, front contact and armature 444, backcontact and armature 445, trunk conductor "490, arinature 659 and itsback contact,

armature 661 and its front contact, conductor 681, armature 837 and itsback contact, wave filter 836 that is resonant to an alternating currentof a frequency of 300 cycles, alternating-current linerelay 803,armature 829 andits back contact to ground. The alternatingcurrentrelays 205 and 803 are energized over the above circuit.

The alternating-currentv the dispatchers office, upon being energized,attracts its armature 243 to cause the operation of the armature 249 ofthe relay' 204.

As a result of the operation of the armature 249,. a. circuit iscompleted extending from ground by way of armature 250 and its frontcontact, armature 249' and its front contact and relay 204 to battery.The relay 204 operates tocomplete a circuit for the relay 203 atarmature 248, and to complete a circuit extending from ground by way offront contact and armature 247. conductor 471 and relay 401 to batteryThe relay 203, upon being energized, opens one pointin the lockingcircuits of the relays 209 and 210 at armature 246, and completes acircuit extending from Y ground by way of armature 17 9and its backcontact, conductor 11, armature 257 and its back contact, armature 245and its front con' tact, relay 202 and relay 203 to battery. The

relay 202 is not operated over this circuit' line relay 205 at.

until the original energizing circuit for the relay 203 is opened. Y

The relay 401, upon operating, establishes a locking circuit fortitselfat armature 425 over a path extending from ground by way of groundedconductor 11, back contact and armature 422, armature 425 and its frontcontact and relay 401 to battery, at armature 424 opens another point inthe locking Cir-- cuit of the relay-400,. and at armature 426 completesa circuit extendingfrom ground by way, of the grounded conductor 11,backcontact and armature 422, front contact and'armature 426 and relay417 to battery.

Another result of the operation of the relay 401 is'that, at armature423, a circuit is completed extending from ground by way of saidarmatureand its front contact, condoctor 470, armature 241 and its'backcontact,

conductor 16, armature 150 and its back contact, relay 112, back contactand armature 153, andback contact and armature 180 to battery;

Therelay 112 is energized over the above circuitand operates to completea-circuit extending from ground by way of armature 1'78 and. its backcont-act, armature 1'52 and its front contact, winding of relay 111,winding of relay 112,-back cont-act and armature 153 and back contactand armature 180 to reason of the fact that it is short-circuited solong as the original energizing circuit of th relay 112 is completed.

The relay 417, upon being energized over battery. The relay 111'is notoperated by I the previously traced circuit, operates to complete acircuit extending from battery by way of armature 460 and its frontcontact, back contact and armature 461, relay 411 and back contact andarmature 447 to ground. The relay 411, upon being energized, preparesonepoint in the circuit of the relay 412 at armature 446 and at armature445 opens one point in the circuits of the alternating-current linerelays 20 5 and 803 at the dispatchers office and substation,respectively.

The relay 205,upon being deenergized, permits the relay 204 to becomedeenergized. As a result of the deenfergization of the relay 204, theoriginal energizing circuit of the re lay 401 is opened at armature 247and the original energizing circuit of the relay 203 is opened atarmature 248.- As a result of the opening of the original energizingcircuit of the relay 203, the short-circuit is removed from the relay202 and this relay is permitted .241 opens a point in the originalenergizing circuit of the counting relay 112. By thelatter operation,the short-circuit is removed I way of armature 178 and its back contact,ar-

mature 176 and its back contact,armature 151 and its front contact,conductor 31, spring 344 of switching relay Y310 and its Working contactand selectingfrelay 309 to battery. The selecting relay 309 is operatedto prepare certain signalling circuits at springs 332, 333 and 334 andto prepare a circuit for the relay 413 at spring 330.

The relay 803, upon being energized, operates its armature 828 to bringabout the engagement of the armature 834 of the relay 802 with its frontcontact. The relay 802 is immediately energized over a circuit extendingfrom ground by Way of armature 835 and its front contact, armature 834and its front contact and relay 802 to battery. The relay 802 operatesits armature, thereby closing a circuit for the relay 801 at armatureS33, and completing a circuit extending from ground by Way of armature832 and its front contact, conductor 680 and relay 609 to battery.

The relay 801 is energized andoperates to open one point in the circuitsof the relays 807 and 808 at armature 831, and at armature 830 completesa circuit extending from ground by Way of armature 778 and its backcontact, conductor 582, back contact and armature 844, armature 830 andits front bontact, relay 800 and relay 801 to battery. The

above circuit is not effective until the original energizing circuit ofthe relay 801 is opened.

The relay 609, upon being operated, opens one point in'the lockingcircuit ofthe relay 608 at armature 643, establishes a locking circuitfor'itself at armature 642 and at armature 641 completes'a circuitextending from ground by way of armature 778 and its back contact,conductor 582, back contact and armature 637, front contact and armature641 and relay 610 to battery. Anotherresult of the operation-of therelay 609 is that a circuit is'completed extending from ground by way offront contact and armature 640, conductor, 679, armature 828 and itsback contact, conductor 580, armature 728 and its back .contact, relay700, back contact and armature 771 and back contact and armature 774 tobattery.

The relay 700, upon operating, completes a circuit, at armature 726,extending from ground by Way of armature 777 and its back contact,armature 726 and its front contact, relay 7 01, relay 700, back contactand armature 771 and back contact and armature 774 to battery. The relay701is not energized over the above circuit by reason of the fact that itis short-circuited as long as the original energizing circuit for therelay 700 is completed.

The relay 610 isenergized over a-previous ly traced circuit and operatesto complete a circuit extending from battery by way of armature 644 andits front contact, back contact and armature 645, relay 617 and backcontact and armature 658 to ground. The relay 617, upon being energized,"opens the original energizing circuit of the alternatingcurrent linerelay 803, thus permitting this relay to be deenergized. The relay 803,upon retracting its armature, permits the relay 802 to deenergize. Therelay 802, upon retracting its armatures, opens the original energizingcircuit of the relay 609 at armature 832, and at armature 833 opens theoriginal energizing circuit of the relay 801. The latter operationpermits the relay 800 to energize. The relay -800, upon operating,

opens another point in the original energizand at armature 828 removesthe short-circuit from thewindingof the relay 701.

The relay 701, upon being energized,prepares a circuit for the relay 712at armature 727, opens another point in the original energizing circuitof the relay 700 at armature 1ng circuit of the relay 803 at armature829,

728, and at armature 729 completes a circuit extending from groundby Wayof armature 777 and its back contact, armature 750 and its back contact,armature 7 29 and its front contact, conductor 575, spring 546 and itsWorking contact and selecting relay 500 to battery. The selecting relay500 is operated to complete certain signalling circuits at springs 521,522 and 523, and to prepare a circuit for the relay 615 at spring 524.

The selecting relays 309 and 500 at the'dis patchers ofice andsubstation, respectively,

are now energized and a signalling circuit is completed extending fromthe ungrounded brush of the 900 cycle generator Gr-1 by Way of spring228 of key K--1 and its Working contact, spring 226 ofkey K and itsWorking contact, conductor 12, spring 334 and its Working contact, wavefilter 395 that is resonant to alternating currents of frequencies of 700 and 900 cycles, conductor 489, trunk con ductor 490, conductor 670,Wave filter 531 that is resonant to alternating current of a frequencyof 900 cycles, and alternatingcurrent relay 511 to ground. Thealternating-current relayf511 is energized over the i above circuit andattracts its armature 536 to cause the armature 534 in the relay 510 tobe forced into engagement with its working contact. As a result of thisoperation, a circuit is completed extending from ground by way ofarmature 535 and its front contact, armature 534 and its front contactand relay 510 to battery. The relay 510 is operated over this circuitand attracts its armature 533 to complete a circuit extending frombattery by way ofsaid armature andits front contact, spring 522 anditsworking contact, conductor 561 and relay 810 to ground.

The relay 810 operates to open the locking circuit of the relay 809 atarmature 853, to

prepare a locking circuit for itself at armature 854, to prepare a pointin the control circuit at armature 855 and to complete a circuit atarmature 856 for the closing coil 812 of the circuit breaker C. Theclosing coil 812 is energized in series with the low-resistance relay825 and operates'to close (the circuit breaker. The closure of thecircuit breaker may bring about any desiredresult at the station.

The relay 809, upon being deenergized, opens one point in the circuit ofthe tripping relay 813 at armature 852, establishes a locking circuitfor the relay 810 at armature 851 and at armature 849 removes groundfrom the conductor 563.

One of the results of the closure of the cir- 1 cuit breaker C is thatthe circuit of the relay 825 is opened. The relay 825, upon operating,completes a circuit extending from ground by way of front contact andarmature 886, armature 874 and its front contact, ar-

' mature 871 and its back contact and relay 818 from the relay 819 andthis relay is energized f tor 563, and the ungrounded pole of the geninseries with the relay 818. The relay 819, upon being energized, preparesa circuit for the relay 823 at. armature 873 and prepares another pointin the circuit of the relay 817 at armature 872. V

' Another result of the closure of the circuit breaker C is that therelay 811 is energized. As a result of this operation, ground fromarmature 854 is placed upon the conducerator G6, that creates analternating current of a frequency of 1300 cycles, is connected toconductor 560. The grounding of conductor 563'completes a circuit whichextends from said grounded conductor, working contact of spring 524 andsaid spring, conductor 676, and relay 615 to battery. The relay I 615,upon operating, completes a circuit forthe relay 612 at armature 655and, at armatures 656 and 657, completes a circuit which extends fromground by way of front contact and armature 660, armature 653 and itsback contact, front contact and armature 657, relay 616, armature 656and its front contact and back contact and armature 652 to battery. Therelay 616 is energized over the above circuit and, upon operating,establishes a locking circuit for itself at armature 658, and at theback contact of this armature opens the circuit of the relay 617. Therelay 617 is deenergized to open the original energizing circuit ofthe-relay 616 at armature 660 and to prepare one point in the controlcircuit at armature 65.9.- g

' The relay 612, upon operating, opens one point in the locking circuitof the relay 613 at armature 647, establishes a locking circuit foritself at armature 646, and completes a circuit at armature 648extending from ground byway of armature 651 and its back contact, frontcontact and armature 648, conductor 684 and rela 804 to battery. Therelay 804 operates to I isconnect' the alternatingcurrent relay 803 fromthe control circuit and connects the alternating-current line relay 806thereto.

It will be remembered that, when the relay 811 is operated by theoperation of the circuit breaker C, the ungrounded brush of thegenerator G6 is connected to the conductor 560. As a resultof thisoperation, a circuit is completed extending from said, ungrounded brush,front contact and armature 857, alternating-current relay 895, conductor560, working contact of spring 521 and said spring, wave filter 595 thatis resonant to alternating current of frequencies of 1100 and 1300cycles, conductor 670, trunk conductor 490, conductor 489, wave filter361 that is resonant to an alternating current of a frequency of 1300cycles and alternating-current relay 318 to ground. 1

The relay 318 operates its armature 360 to cause the armature 358 of therelay 316 to engage its working contact. As a result of this operation,the relay 316 is energized over a circuit extending from ground by wayof armature 359 and its front contact, armature 358 and its frontcontact and relay 316 to battery. The relay 316 immediately operates tocomplete a circuit at armature 357 which extends from groundby way offront contact and said armature,.spring 333 audits working contact,conductor 14 and relay 201 to battery.

The relay 201 is immediately energized to open the locking circuit ofthe relay 200 at armature 240, to prepare a locking circuit for itselfatlarmature 239, to place ground upon the conductor 13 at armature 238,and to complete a circuit'for the signalling lamp 232 at armature 237The relay 200 is deenergized to complete a locking circuit for the relay201 at armature 235, and to extinguish the signalling lamp 231 atarmature 233. The change in supervisory signals notifies the dispatcherthat the circuit breaker at the substation has been operated.

By the grounding of conductor 13, a cirimitate cuit is completed whichextends by Way of said conductor, Working contact of spring 330 and saidspring, conductor 483, and relay 413 to battery. The relay 413 isenergized tocomplete a circuit for the relay 416 at armature 448 and tocomplete a circuit for the relay 412 at armatures 449 and 450 over apath which extends from ground by Way of front contact and armature 446,armature 452 andits back contact, front contact and. armature 450, relay412, armature 449 and its front contact and back contact and armature451 to battery.

The relay 416, upon operating, establishes a locking circuit for itselfat armature 457, opens one point in the locking circuit of the relay 415at armature 458 and at armature 459 completes a circuit Which extendsfrom ground by Way of armature 456 and its back contact, front contactand armature 459, conductor 477 and relay 206 to battery. The relay 206operates to disconnect the alternating-current line relay 205 from thecontrol circuit and connects the alternating-current line relay 208thereto.

Upon operating, the relay 412 opens the circuit of the relay 411 atarmature 447 and at the front- Contact of this armature establishes alocking circuit for itself. The relay 411, upon being deenergized,restores one point in the control circuitat armature 445 and at armature446 opens the original energizing circuit of the relay 412.

The control circuit is now completed and extends from ground by way ofback contact and armature 261, alternating-current line relay 208, wavefilter 252 that is resonant to an alternating current of a frequency of500 cycles, front contact and armature 251, conductor 474, front contactand armature 444, back contact and armature 445, trunk conductor 490,armature 659 and its back contact, armature 661 and its front contact,conductor 681, armature 837 and its front contact, Wave filter 838 thatis resonant to an alternating current of a frequency of 500 cycles,alternating-current line relay 806,,and armature 848 and its backcontact to the ungrounded brush of the ,generator'G5 that creates analternating current of 500 cycles. The line relays 806 and 208 areenergized over this circuit.

The line relay 208, at the dispatchers oflice, upon being operated,attracts its armature 260 to force the armature 255 of the relay 207into engagement with its Working contact. As a result of this operation,a circuit is completed for the relay 207 extending from ground by Way ofarmature 256 and its front contact, armature 255 and its front contactand relay 207-to battery.

The relay 207 is energized to complete a circuit for the relay 209 atarmature 254 and to complete a circuit at armature 253 extending fromground by Way of said armature and its front contact, conductor 473 andrelay 400 to battery. The relay 209, upon be- 111g energized, opens thelocking circuit of the relays 202 and 203 at armature 257 and prepares acircuit for the relay 210 at armature 256. The relay 202 is deenergizedto prepare a circuit for the relay 203 at armature 242 and to prepare acircuit for the relay 205 atarmature 244. The relay 203 is deenergizedto complete a circuit extending from ground by Way of armature 179 andits back contact, conductor 11, back contact and armature 246, armature256 and its front contact, relay 210 and relay 209 to battery. Thecircuit traced above is not effective until the original energizingcircuit for the relay 209 is opened. I

The relay 400, upon being energized, opens the locking circuit of therelay 401 at armature 422, opens the circuit of the relay 417 at thissame armature, prepares a locking circuit for itself at armature 421 andat armature 420 prepares a circuit for the relay 418. The relay 401,upon being deenergized, establishes a locking circuit for the relay 400to grounded conductor 11 and also completes a circuit for the relay 418at armature 424. The relay 417, upon being deenergized, opens onepointin the circuit of the relay 411 at armature 460 and preparesanother circuit for this relay at the back contact of this samearmature. The relay 418, upon being. energized, prepares a circuit forthe relay 411.

Another result of the operation of the relay 400 is that, at armature419, a circuit is completed extending from ground by Way of saidarmature and its front contact, conductor 472, armature 258 and its backcontact, co'nductor 17, front contact and armature 149, armature 174 andits back contact, relay 124, back contact and armature 153 and back con-L tactand armature 180 to battery. The relay 124, upon being operated,opens the circuit of the selecting relay 309 at armature 176 and, at thefront contact of this armature, completes a circuit for the relay 123.The latter circuit is not effective until the original energizingcircuit of the relay 124 is opened.

The relay 309, upon being deenergized, opens certain signalling circuitsat the springs 332, 333 and 334, and at the spring 330 removes groundfromthe conductor 483, thereby opening the circuit of the relay 413. Therelay 413, upon being deenergized, opens one point in the originalenergizing circuit of the relay 416 at armature 448 and at armature orcontrol circuit. As a result of the opening of the control circuit, thealternating-current line relay 208 is deenergized to open the circuit ofthe relay 207. The relay 207 is deenergized to open one point in theoriginal energizing circuit of the relay 400 at armature 253 and to openone point in the original energizing circuit of the relay 209 atarmature 254. As a result of the latter operation, the short-circuit isremoved from the relay 210 and this relay is operated. Upon operating,the relay 210 opens another point in the original energizing circuit ofthe relay 209 at armature 259, opens another point in the circuit of therelay 208 at armature 261, and at armature 258 removes the short-circuitfrom the winding of the relay 123. The relay 123 is now energized.

Upon operating, the relay 123 prepares a point in the circuit of therelay 110 at armature 173, opens another point in the originalenergizing circuit of the relay 124 at armature 174 and at armature 175completes a circuit which extends from'ground by way of armature 178 andits back contact, armature 148 and its back contact,.armature 175 andits front contact, conductor 30, spring 343 and its working contact andselecting relay 308 to battery. The relay 308 is energized over theabove circuit and operates to prepare certain signalling circuits in thesame manner as the operation of the relay 309.

Inasmuch as the key associated with the particular apparatus unit that.is selected by the operation of the relay 308 has not been operated bythe dispatcher, tlIEIC'Wlll be no signalling circuit completed from thedispatchers ofiice. Inasmuch as the particular apparatus unit at thesubstation that is adapted to be selected by the operation of theselecting relay 308 is not operated, there will be no signalling circuitcompleted from the substation.

By reason of the fact that the key associated with this particularapparatus unit is not operated, the conductor 19 will be groundedthrough relays, such as 200 associated with lines 13 over key K and 201,that are associated with the particular key to which the conductor 19extends. The ground on the conductor 19 extends by way of the workingcontact of spring 328 and said spring, conductor 484 and relay 414 tobattery.

The relay 414 is operated to complete a circuit for the relay 415 atarmature 453 and to complete a circuit for the relay 412 at ture 451 tobattery. The relay 415, upon being energized, opens the locking circuitof the relay 416 at armature 454, prepares a. locking circuit for itselfat armature 455, and at armature 456 opens the circuit of the relay 206.The relay 416 is deenergized to establish the locking circuitof therelay 415.

The relay 206 is deenergized to disconnect the alternating-current linerela 208 from the control circuit and connect t e 211- ternating-currentline relay 205 thereto.

The relay 412, upon being energized, opens the circuit of the relay 411at armature 447 and at the front contact of this armature establishes alocking circuit for; itself. The relay 411, upon being deenergized,opens the original energizing circuit of the relay 412 at armature446and at armature 445 prepares another point in the control circuit.

At the substation, the relay 806, upon being energized, at armature 847,forces the armature 841 of the relay 805 into engagement with itsworking contact. As a result of this operation, a circuit is completedextending from ground by way of armature '842 and its front contact,armature 841 and its front contact and relay 805 to battery. The relay805 is energized to complete a circ'uit for the relay 807 at armature840 and to complete a circuit ex'tendingfrom ground upon beingdeenergized, completes a circuit which extends from the groundedconductor 582, back contact and armature 831, armaand relay 807 tobattery. I This circuit is not effective so long as the originalenergizing circuit of the relay 807 is completed.

The relay 608, upon being energized, prepares a locking circuit foritself at armature 638, prepares a circuit for the relay 611 at armature639, opens the locking circuit of the relay 609 at armature 637 and alsoopens the circuit of the relay 610 at this same armature. The relay 609,upon being deenergized, establishes a locking circuit for the relay 608at armature 643 and completes a circuit for the relay 611 at this samearmature. The relay 610, upon being deenergized, opens one point in thecircuit of the relay 617 at armature 644 and at the back contact of thisarmature prepares another circuit for the said relay. The relay 611,

, upon being energized, prepares another point in the circuit of therelay 617.

Another result of the operation of the relay 608 is that a circuit is.completed exvture 843 and its front contact, relay 808 the front contactof this armature, to com;

plete a circuit for the relay 713. The cir cuit for the relay 713 is notefiective until the original energizing circuit, of therelay 712 isopened.

The relay- 500., upon being deenergized, opens certain points in thesignalling circuit and also removes ground from the conductor 676,thereby opening .the circuit of the relay 615. The relay 615isdeenergized to open the original energizing circuit of the relay 612and to open the circuit .of the relay 616. The

relay 616 is 'deenergized to complete a circuit which extends fromground by Way of armature 658 and its back contact, relay 617, armature645 and its front contact, and back con-' tact and armature 644 tobattery. The relay 617 operates to prepare a point in thecircuit of therelay 616 at armature 660, and at armature 659 opens another point inthe trunk or control circuit.

As a result of the opening of the control circuit, thealternating-current line relay 806 is deenergized and the circuit of therelay 805 is .opened. The relay 805, upon being deenergized, opens theoriginal energizing circuit of the relay 608 at armature 839, and atarmature 840 removes the short-circuit from the winding of the relay808. The relay 808 a 40 immediately operates to open'another point inthe original energizing circuit of the relay 807 at armature 846, and atarmature 848 opens another point in the circuit of the relay 806.

Another result of the operation of the relay 808 is that, at armature845, the short-circuit is removed from the winding of the relay 713 andthis relay is energized. Upon operating,

. the relay 713' prepares a point in the circuit of the relay 702 atarmature 751, opens another point in the original energizing circuit ofthe relay 712 at armature 752, and at armature 7.53 completes a circuit.extending from ground by way of armature 777 and its back contact,armature 730 and its back contact, ar-

mature 753 and its front contact, conductor 574, spring 547 and itsworking contact and selecting relay 501 to battery.

' The selecting relay 501 operates to prepare certain signallingcircuits. Another result of the operation of the selecting relay is thatthe conductor 675 is grounded. This is true by reason of the fact thatthe conductor 599 extends to relays, such as 809 to 811, inclusive,

associated with another circuit breaker, such.

as C, in the same manner that the conductor 563 extends to the relays809 to 811, inclusive. Ground'is present upon-this conductor by reasonof the fact that no action of the associated circuit breaker hasoccurred.

The grounding of the conductor 67 5 causes the energization of the relay614. The relay 614, upon being operated, completes acircuit for therelay 613 at armature 654, and at armatures 652 and 653 completes acircuit for the relay 61 6. The relay'613, upon being energized, opensthe locking circuit of the relay 612 at armature 649, prepares a pointin its locking circuit at armature 650, and at armature 65L opens thecircuit of the relay 804. The relay 612, upon being deenergized,establishes the locking circuit of the relay'6l 3 at armature 647. Therelay 804,

upon being deenergized, disconnects the alternating-current line relay806 from the control circuit and connects the line relay 803 thereto.The relay 616 is energized over a circuit extending from ground by wayof front-contact and armature 660, armature 653 andits front contact,back contact and armature 657, relay 616, armature 656 and its backcontact, and front contact and armature 652to battery.

Y The relay 616, upon being operated, completes a locking circuit foritself at armature 658 and at the back contact of this armature opensthe circuit of the relay 617. The relay 617 is .deenergized to open theoriginal ener- I gizing circuit of the relay 616 at armature 660 and tocomplete the control circuit at armature 659.

The control circuit extends from the ungrounded brush of the generatorG-3 which generates an alternating-current of a frequency of 300 cycles,by way of back contact and armature 244, relay 205, wave filter 250,back contact I and armature 251, conductor 474, front contact andarmature 444, back contact and armature 445, trunk conductor 490,armature 659 and its back contact, armature 661 and its front contact,conductor 681, armature 837 and its back contact, wave filter 836, relay803 and armature 829 and its back contact to ground; The relays 205 and803 are energized over this circuit.

The operation will now proceed in substantially the same manner as hasbeen described previously. Thus, by the operation of the controlcircuit, the relays 110 and 109, 122 and 121,108 and 107, 120 and 119,106 and 105, 118 and 117, 104 and 103, 116 and 115 and 102. and 101 atthe dispatchers otfice are energized in the sequence mentioned. Theselecting relays 307, 306, 305, 304, 303, 302, 301 and 300 are energizedin substantially the same manner as before described.

Thecircuit of the relay 102 is completed by ,the energization of theline relay 205, causing the energization of the relay 204 which, inturn, brings about the operation of the relay 401. The relay 102, uponoperating,

opens the circuit of the selecting relay 300 at armature 132 and at thefront contact of this armature completes a circuit for the relay 101which is effective when the circuit for the relay 102 is opened by theoperation of the relay 202, which is brought about by the actherebyopening the circuit of the relay 412.

The relay 412 is deenergized to complete a circuit for the. relay 411.The relay 411 operates to open one point in the control circuit atarmature 445 and to prepare a point ,the consequent deenergizationof'the relay 204. The retraction of the armatures of the battery.

in the circuit of the relay 412 at armature The opening of the controlcircuit causes the deenergization of the line relay 205 and relay 204removes the short-circuit from the winding of the relay 202 and permitsthis relay to be energized. The relay 202 operates to remove theshort-circuit from the winding of the relay 101 and this relay isenergized I to prepare a circuit for the relay 114 at armature 129, toopen one point in the original energizing circuit of the relay 102 atarmature 130, and to complete a circuit extending from ground by way ofarmature 178 and its back contact, armature 156 and its back contact,armature 131 and its front contact, conductor 21, and relay 314 tobattery. The relay 314 is energized over this circuit and operates toplace ground upon the conductor 483 at armature 351, and at armature352, to

complete a circuit extending from ground by* way of said armature andits front contact, conductor 487, armature 440 and its back contact,relay 409, back contact and armature 433, and back contact and armature431 to The relay 409 operates to open the circuit of the switching relay310 at armature 442, and at armature 443 completes a circuit extendingfrom ground by way of back contact and armature 428, armature 443 andits front contact, relay 408, relay 409,.back contact and armature 433and armature 431 to battery.

As a result of the deenergization of the switching relay 310, the firstgroup of selecting relays is disconnected from the control of thecounting relays.

,The grounding of conductor 483 brings about the energization ofthe-relay 413, and

the operation of the relays 412 and 416. The relay 416 operates to openthe circuit of the relay 415 and to prepare a circuit for the .'relay206. The relay 415, upon being deenergized, brings about theenergization of the relay 206 and the establishment of a locking circuitfor the relay 416. The operation of the relay 412 opens the circuit ofthe relay 411. The relay 411 is deenergized to prepare a circuit for theline relay 208 and to open one point in the original energizing circuitof the relay 412.

At the substation, the relays 702 and 703, 714 and 715, 704 and 705, 716and 717, 706 and 707, 718 and 719, 708 and 709, 720 and 721 and 710and711 are energized in the sequence mentioned by the operation of thetwo line relays 803 and 806 under the control of the control circuit.The selecting relays 502 to 509, inclusive, are energized in a mannersimilar to that described. The operation of the,

corresponding selecting relays at the dispatchers ofiice and at thesubstation takes place simultaneously, that is, the correspondingselecting relays at both the dispatchers office and the substation areenergized together. The signalling circuits function in identically thesame manner as before described.

The relay 710 is energized by the operation of the line relay 803,bringing about the energization of the relay 802 and the relay 609. Uponoperating, the relay 710 opens the circuit of the'selecting relay 509 atarmature 746 and at the front contact of this armature completes acircuit for the relay 711; This circuit is not effective so long as theoriginal energizing circuit of the relay 710 is maintained,

The deenergization of the selecting relay 509 causes the removal ofground from conductor 675, thus permitting the relay 614 to bedeenergized. The relay 614, upon being deenergized, causes the releaseof the relay 616. The deenergization of the relay 616 brings about theoperation of the relay 617 which opens one point in the control circuit.

The opening of the control circuit brings about the deenergization ofthe relay 802. The release of the relay 802 permits the relay 800 to beenergized. The energization of the relay 800 brings about the removal ofthe short-circuit from the winding of the relay 711 and this relay isoperated. The relay 711, upon being energized, prepares a circuit forthe relay 722 at armature 747, opens one point in the originalenergizing circuit of the relay 710 at armature 748 and at armature 749completes a circuit extending from ground by way of armature 777 and itsback contact,

armature 770 and its back contact, armature 749 and its front contact,conductor 565, and relay 514 to battery.

The relay 514 is energized to place ground upon the conductor 676 atarmature 541 and to complete a circuit at armature 542 whichground uponthe conductor 687 at the front contact of this armature, from 877, andto complete a circuit extending from ground by way "of back contactandarmature 634, armature 620 and its front contact, relay 601, relay600, back contact and armature 630, and back contact and armature 632 tobattery. This circuit is not elfective so long as the originahenergizingcircu it of the relay 600 Y is completed.

The grounding of conductor 676 brings about the energization of therelay 615. The relay 615 upon operating, completes a circuit for therelay 612 and also for the relay 616. The relay 612, upon beingenergized, opens the locking circuit of the relay 613, prepares alocking circuit for itself and establishes a circuit for the relay 804.The deenergization ofthe relay 613 brings about the completion of thelocking circuit and also the energization of the relay 804. The relay804 operates; to connect the line relay 806 in the control circuit.

The r lay 616, upon being energized, establishes a locking circuit foritself at armature 658, and at the back contact of this same armatureopens the circuitof therelay .617; The-relay 617 is deenergized tocomplete the trunk or control circuit. The line relays 208 and 806 arenow energized in series.

The line relay 208 operates to cause the energization of the relay 207.Therelay 207 operate's to complete a circuit for the relay 209 and-alsofor the relay 400. The relay 209 is energized to complete acircuit'forthe relay I 409 at armature 440, to prepare'a circuit for,

210 which is 'efiective when the original energizing circuit of therelay 209 is opened, and to openthe locking circuits of the relays 202and 203.which are deenergized. The relay 400 operates to bring about therelease of therelay 401 and the consequent deenergization of the relay417 and the energization of the relay 418. i

Another result of the operation of the re lay 400 is that a circuit iscompleted for the counting relay 114. The counting relay 114 is operatedto open the circuit of the rela 314 at armature 156 and to establish. acircult for the r elay 113-atthe front contact of this armature; Therelay 113 is'not energized until the original energizingcircuit of therelay 114 is opened. Therelay 314, upon being deenergized, removesgroundfrom the cogductor 483 and also from the conductor 48 y The nemovalofground from the conductor 487 causes the energization ofthe relay 408.

The relay 408 operates to open another point in the original energizingcircuit of the relay the relay? 467 atthe front contact of this arma=ture, and to establish a circuit at armature 441 whichextends fromground by Way of front contact and armature 276', conductor 478, backcontact'a-nd armature 429, armaand armature 438, conductor 486 andswitching relay 311'to battery. The switching relay 311 is energizedtoconnect the second group of selecting relaysunder the control of thecounting relays.

Asa result of the removal of ground from conductor 483, the relay 413 isdeenergized and the relay 412 is released. Asa result of thedeenergization of the relay 412, a circuit is completed for the relay411 and this relay is operated to open one point in the controlcircuitatarmature 445 and to preparea circuit, for the relay 412 atarmature. 446.

The opening of the control circuit brings true 441 and its frontcontact, back contact about the deenergization of the relay 208 and i'upon being deenergized, removes the shortcircuit from the re ay'"210and this relay is operated to open another point inthe circuit of theline'relay 208, and to. remove the shortcircuit from y 3- I a The relay113, upon operating, opens another point in the original energizingcircuit the winding of the counting reof the relay 114 at armature 154,removes the short-circuit from the relay 126, thus permitting this relaytoenergize in series with all the counting relays at arma'ture153, and

circuit extending from ground by way of armature 7 and its back contact,armature relay 313 to battery.

P The relay 313 is energized to place round upon the conductor 484. Thegroun ing of v .at armature 155 to momentarily complete a ,155and itsfront contact, conduetor20 and I is operated to open the locking circuitof the i v relay 416 and to'open the circuit of the relay 206. The relay206 is deenergizedto disconmet the line relay 208 from the controlcircuit'and to connectathe line relay 20 5 there- The rela 412,"uponbeing ener ized, establishes *a lb cking "circuit for itsel and opensthe cilbuit-ofthe relay 4131, which is deener circuit.

gized to complete a point inthe control J The relay. 126, ,u'pon beingoperated over 1 a previously traced circuit, brings about theenergization of the slow-acting relay 125, The relay is operated to openthe circuit of the relay 313 at armature'177,'to open the circuits.ofail-the counting relays 101 to 124',

inclusive, atarm'ature 178, to remove ground from the conductor 11"altar-mature "179;, and

to place ground upon the conductor 10 at the front contact of thisarmature.

- The removal of ground from-th econductoi' 11 brings about thedeenergization of the re relay 415 is deenergized .to restore certaincircuits to normal.

As a result of the grounding of 10, therelay 211 is energized andoperates to establish a locking circuit for itself at armature 262, toopen the circuit of therelays 213 and 214 at armature 263 and to openthe circuit of the relay 410 at armature 264. The relay410 isdeenergized to prepare a circuit for the-rclay 222. The relay 213 isdeenergized to open the circuit of the relay 215.

The relay 214 is deenergized to prepare a cir-' cuit for the relay .213and to prepare another point in the circuit of the relay 222. The relay215 is deenergized to complete a circuit which will be describedhereinafter.

.The operation of the line relay 806 at the sub-station causes theoperation of the relay 805. The relay 805 operates to close a circuitfor the relay 807 and'also a circuit for the relay 608. The relay 807prepares a circuit for the relay 808, which is effective upon theopening of the original energizing circuit of the relay' '807, and opensthe locking circuits of the relays 800 and 801, which are de energizedto restore certain circuits to normal.

the deenergization of the relay 609, the de energization of the relay611 and, also, the cleenergization of the relay 610. The relay 609 isdeenergized to restore certain circuits to normal. The relay 610 -isdeenergized to prepare a circuit for the relay 617 and the relay 611 isdecnergized for the same purpose.

Anotherresult of the operation of the relay 608 is that a circuit iscompleted for the counting relay. 722. The relay 722 is energized toopen the circuit of the relay 514 and to prepare a circuit for the relay723, which is effective upon the opening of the original energizingcircuit for the relay 7 22. Therelay 514 is deenergized to remove groundfrom the conductors 67 2: and 676.

The'removal of ground from the conductor 672 permits the relay 601 to beenergized. The relay 601 operates to open another point in the originalenergizing circuit of the relay I 600 and to prepare a circuit for therelay 602. Another result of the operation of the relay 601'is that acircuit is completed extendlng from ground by way of front contact andarmature 877, conductor 685, back contact and armature 635', armature622 and its front contact, back contact and armature 623,conductor 67 3and switching relay 517 to battery. The switching relay 517 is energizedto conconductor The operation of therelay 608 brings aboutrelay 615. Therelay 615 is deenergized to open the circuit'of the relay 616." Therelay 616 is deenergized to complete a circuit for the relay 617. Therelay 617 operates to prepare a circuit for the relay 616 and open itone point in the control circuit. t

As a result of theopening of the control circuit, the line relay 806 isdeenergized, as

is the relay 805. As a result of the deenergization of the relay 805,the relay 808-is permitted to energize. The relay 808 operates to openanother point in the circuit of the relay '806 and to remove theshort-circuit from the relay 723. The relay 723 is operated to removethe short-circuit from the relay 7 24 at armature 771, therebypermitting this relay to energize in series with the counting relays, to

open another point in the circuit of the relay 7 22 at armature 772, andto complete a circuit extending from ground by way of armature 776 andits back contact, armature 773 and its front contact, conductor 564 andrelay 515 to battery. 4

The relay 515 is energized to place ground upon the conductor 675 atarmature 543. The

grounding of conductor 67 5 brings about the energization of the relay614. The relay 614 operates to complete a circuit for the relay 613, andto complete a circuit for the relayv 616. .The relay 613 operates toopen the locking circuit of the relay 612, thus permitting this relay todeenergize. and to open the circuit of the relay 804. The retraction ofthe armature 837 of the relay 804 disconnects the line relay 806from-the control circuit and connects the line relay 803 thereto.

The relay 616 is operated to establish a locking circuit for itself andto open the circuit of the relay 617. The relay 617 is deen ergized tocomplete the control circuit.

The relay 724 is energized in series with the counting relays and bringsabout the operation of the relay 725. The relay 725 operates to open thecircuit of the relay 515 at armature 776, to open the circuit of all thecounting relays 700 to 723, inclusive. at armature 777, to remove groundfrom the conductor 582 and to place ground upon the conductor 583 atarmature 728.

the relay 614 which permits the relay 616 to be deenergized. The releaseof the counting relays restores certain circuits to their normalcondition.

The relay 515 is deeiiergized to bring about the deenergization of Theremoval of ground-fromcouductor 582 7

